PROJECT SUMMARY Urologic chronic pelvic pain (UCPP) syndromes, commonly diagnosed as interstitial cystitis/bladder pain syndrome (IC/BPS) or chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS), represent the most common type of chronic visceral pain disorders. Although dysregulation of peripheral inputs from the viscera likely account for a number of the symptoms of the diseases, a failure to understand and treat central nervous system (CNS) changes likely prevents complete recovery for affected patients. The long-term goal of our lab is to understand the extent to which areas in the brain are responsible for the development and maintenance of persistent pain and accompanying affective disturbances that exist within urologic conditions. We aim to discover and develop novel CNS treatment paradigms for this disease to complement approaches directed at the bladder. Recent evidence has suggested that the central amygdala in the CNS may be an important locus for the interaction between visceral pain and anxiety, potentially serving as a driver for chronic conditions like UCPP. By determining the role of the amygdala in animal models of bladder pain, insight will be provided into the underlying physiology of the human condition. Evidence from human and animal models has shown that the left and right amygdala may differentially regulate pain. Variances in left and right hemisphere activation are well described in human language production, visual processing, and complex planning tasks. [Functional lateralization exists in emotional processing areas of the brain, including the amygdala, across multiple taxa including birds and mammals where the right brain serves as a reactive center to stress and injury. This conservation suggests that lateralization of limbic circuits is likely an evolutionarily important phenomenon.] The idea that dysregulation in lateralization might also play a significant role in disease is a novel concept with important clinical relevance. UCPP patients show lateralized changes in amygdala gray matter and lateralized amygdala functional connectivity to other areas in the CNS. The molecular mediators responsible for incoming information to the left versus right amygdala remain unknown. The objective of this proposal is to determine the extent of bladder pain lateralization between the left and right central amygdalae and the molecular mechanisms responsible for this phenomenon. This objective will be met through two distinct but complementary specific aims. In Aim 1 of this proposal, we will determine the extent of left and right amygdala activation following stimulation of control or sensitized bladders, while also probing the areas of the brain through which nociceptive information travels. In Aim 2, we will manipulate specific brainstem projections to the amygdala to determine which cells are sufficient and necessary for lateralized pain-like output in both control and sensitized conditions. Overall, this proposal will help determine the extent and mechanisms of amygdala activation during painful bladder stimulation and the mechanisms by which an overactive amygdala may contribute to bladder pain as seen in UCPP.